Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid contains all of the digits from 1 to 9.
Basic Rules:
Each row must contain all of the digits from 1 to 9.
Each column must contain all of the digits from 1 to 9.
Each of the nine 3x3 subgrids (also called "boxes" or "blocks") must contain all of the digits from 1 to 9.
The same number cannot appear twice in the same row, column, or 3x3 subgrid.
The puzzle starts with some cells already filled in (pre-filled numbers). These cannot be changed.
The goal is to fill the remaining empty cells.
How to Play this Game:
**Select a Cell:** Click on any empty cell in the grid to select it.
**Enter a Number:** Use the number pad (1-9) below the grid to enter a number into the selected cell.
**Clear a Cell:** Click the "Clear Cell" button to remove a number you've placed.
**Highlights:** Selected cells, their row, column, and subgrid will be highlighted to help you.
**Error Feedback:** If you place a number incorrectly, the cell will highlight in red. You will lose a life.
**Lives:** You have a limited number of lives (hearts). Losing all lives will result in a "Game Over."
**New Game:** Click "New Game" to start a fresh puzzle with a different difficulty.
**Solve Puzzle:** If you're stuck, use "Solve Puzzle" to see the complete solution (but this will end your current game).